The overarching aim of this program of research is to use Magnetic Resonance Imaging (MRI) methodologies to identify the neurobiological basis of developmental neuropsychiatric disorders, and in several disease areas in particular: 1) Disorders of impulse control, including Tourette's syndrome (TS), Obsessive-Compulsive Disorder (OCD), and Attention-Deficit/Hyperactivity Disorder (ADHD); 2) Conditions that confer risk for disturbances in development of the neonatal brain, including premature birth and prenatal exposure to drugs of abuse; and 3) Affective Disorders. A substantial portion of his work also involves the development of new methods for processing MRI data and for translational research involving behavioral neuroscience paradigms within the MRI scanner, as well as mentoring junior investigators in the application of neuroimaging methodologies to the study of childhood psychiatric disorders. The immediate aims of this Career Development Award (K02) are to (1) obtain sufficient salary support to allow the applicant to continue using MRI methods to define the neurobiological bases of childhood neuropsychiatric disorders; (2) free the applicant of substantial clinical, teaching, and administrative responsibilities, thereby permitting a greater focus of time and energy on research activities; (3) provide the applicant with the opportunity to develop skill sets in MR Spectroscopy (MRS), an MRI modality with which he has only limited experience, but one that promises to reveal further the neurochemical underpinnings of morphological and functional disturbances that the applicant has helped to define in TS, OCD, and ADHD; and (4) conduct an already-funded morphometric study (R01) of 620 children and adults with TS, OCD, or ADHD and to correlate those morphological measures with immunological, neurohumoral, neuropsychological, and family history data.